{"title":"Occurrence of viable but non-culturable (VBNC) pathogenic bacteria in tap water of public places","authors":"Lizheng Guo, Xinyan Xiao, Kassim Chabi, Yiting Zhang, Jingjing Li, Su Yao, Xin Yu","doi":"10.1007/s11783-024-1795-4","DOIUrl":null,"url":null,"abstract":"<p>Viable but non-culturable (VBNC) bacteria have been detected in source water and effluent of drinking water treatment processes, leading to significant underestimation of viable cell counts. Limited information exists on VBNC bacteria in tap water, particularly in public places. To address this gap, a comprehensive nine-month study was conducted in a major city in south-eastern China, using culture-based and quantitative PCR with propidium monoazide (PMA) dye methods. Forty-five samples were collected from five representative public places (railway station, campus, hospital, shopping mall, and institution). The findings revealed that culturable bacteria represented only 0–17.51% of the viable 16S rRNA genes, suggesting that the majority of viable bacteria existed in an uncultured or VBNC state. Notably, opportunistic pathogens such as <i>Escherichia coli</i>, <i>Enterococcus faecalis</i>, <i>Pseudomonas aeruginosa</i>, <i>Salmonella</i> sp., and <i>Shigella</i> sp. were primarily detected as VBNC cells, with concentrations ranging from 1.03 × 10<sup>0</sup> to 3.01 × 10<sup>3</sup>, 1.20 × 10<sup>0</sup> to 1.42 × 10<sup>2</sup>, 1.32 × 10<sup>0</sup> to 8.82 × 10<sup>0</sup>, 1.00 × 10<sup>0</sup> to 6.71 × 10<sup>1</sup>, and 2.07 × 10<sup>0</sup> to 1.93 × 10<sup>2</sup> cell equivalent/100 mL, respectively. Culturable <i>P. aeruginosa</i> was observed in tap water after prolonged stagnation, indicating potential risks associated with bacterial regrowth. Spatial and temporal factors accounted for 17.1% and 26.0%, respectively, of the variation in tap water community structure during the sampling period, as revealed by 16S rRNA amplicon sequencing. This study provides quantitative insights into the occurrence of VBNC bacteria in tap water and highlights the need for more sensitive monitoring methods and microbial control techniques to enhance tap water safety in public locations.</p>","PeriodicalId":12720,"journal":{"name":"Frontiers of Environmental Science & Engineering","volume":null,"pages":null},"PeriodicalIF":6.1000,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers of Environmental Science & Engineering","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1007/s11783-024-1795-4","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 0
Abstract
Viable but non-culturable (VBNC) bacteria have been detected in source water and effluent of drinking water treatment processes, leading to significant underestimation of viable cell counts. Limited information exists on VBNC bacteria in tap water, particularly in public places. To address this gap, a comprehensive nine-month study was conducted in a major city in south-eastern China, using culture-based and quantitative PCR with propidium monoazide (PMA) dye methods. Forty-five samples were collected from five representative public places (railway station, campus, hospital, shopping mall, and institution). The findings revealed that culturable bacteria represented only 0–17.51% of the viable 16S rRNA genes, suggesting that the majority of viable bacteria existed in an uncultured or VBNC state. Notably, opportunistic pathogens such as Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella sp., and Shigella sp. were primarily detected as VBNC cells, with concentrations ranging from 1.03 × 100 to 3.01 × 103, 1.20 × 100 to 1.42 × 102, 1.32 × 100 to 8.82 × 100, 1.00 × 100 to 6.71 × 101, and 2.07 × 100 to 1.93 × 102 cell equivalent/100 mL, respectively. Culturable P. aeruginosa was observed in tap water after prolonged stagnation, indicating potential risks associated with bacterial regrowth. Spatial and temporal factors accounted for 17.1% and 26.0%, respectively, of the variation in tap water community structure during the sampling period, as revealed by 16S rRNA amplicon sequencing. This study provides quantitative insights into the occurrence of VBNC bacteria in tap water and highlights the need for more sensitive monitoring methods and microbial control techniques to enhance tap water safety in public locations.
期刊介绍:
Frontiers of Environmental Science & Engineering (FESE) is an international journal for researchers interested in a wide range of environmental disciplines. The journal''s aim is to advance and disseminate knowledge in all main branches of environmental science & engineering. The journal emphasizes papers in developing fields, as well as papers showing the interaction between environmental disciplines and other disciplines.
FESE is a bi-monthly journal. Its peer-reviewed contents consist of a broad blend of reviews, research papers, policy analyses, short communications, and opinions. Nonscheduled “special issue” and "hot topic", including a review article followed by a couple of related research articles, are organized to publish novel contributions and breaking results on all aspects of environmental field.